The present invention relates to artificial seeds comprising a meristematic tissue and a solid support.
It is known that artificial seeds have become of increasing interest over recent years, these seeds allowing users to have seeds at hand which comprise homogeneous general features and specific genetic features which are well defined, precise, sophisticated, specific and identified, with a view to obtaining well-determined plant varieties.
It is known that artificial seeds can be made which are embedded in various types of support. In particular, it is well known to produce artificial seeds where a meristematic tissue is embedded in a gel, especially a hydrogel. However, this type of artificial seed has a variety of shortcomings connected to the gels themselves:
the gels are very susceptible to the action of microorganisms, in particular to the action of fungi or bacteria; PA1 the gels favorably influence the development of such microorganisms; PA1 to retain their favorable properties, the gels must generally be preserved under specific humidity and temperature conditions, which makes their long-term storage more complicated. PA1 in some cases, the gels are formed by pouring liquid in the hot state, which can lead to destruction or, at least, denaturation of the meristematic tissues; it can also have an effect on the preservation of these meristematic tissues, since their keepability can be reduced by the effect of heat. PA1 a meristematic tissue, that is to say a plant tissue capable of growth so as to give rise to an autonomous and complete plant (or vegetable organism), PA1 a support in contact with said meristematic tissue, and preferably surrounding said meristematic tissue on all sides, this support being PA1 a shell made of polymer material and soluble in water, which surrounds the unit composed of support and meristematic tissue, PA1 a water-tight film which covers the inside of the shell of polymer material.
When gels are formed with the aid of certain substances such as alginates, the ionized molecules which exist in the medium bring about bridge formation between the polymer chains; in consequence, the structure is rendered rigid and the nutrient medium is deplenished.
In general, the gels are gas-impermeable, which adversely affects oxygen supply to the meristematic tissues when they need it. To remedy this problem, it has been proposed to implant the meristematic tissue onto the gel, or onto the edge of the gel, so that part of it is in the air, but this is not advantageous since the meristematic tissue is insufficiently protected and, if the artificial seed is turned over and shaken, the tissue can leave the gel, which destroys the unit.
Nutrients and/or protective agents, in particular pesticides, for assisting the development of the artificial seed must be added when the artificial seed is being prepared and not only when growth gets under way, because of the impermeability of the gels. But this addition may not conform to what is really necessary at the point in time when growth of the seed begins.